The Prognostic Impact of Intraductal Carcinoma of the Prostate: A Systematic Review and Meta-Analysis.

PURPOSE: This systematic review and meta-analysis aimed to assess the prognostic impact of intraductal carcinoma of the prostate in patients with prostate cancer. MATERIALS AND METHODS: A systematic search was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. We searched PubMed®, Web of Science™, the Cochrane Library and Scopus® up to October 2019. The end points were biochemical recurrence-free, cancer specific and overall survival. RESULTS: We identified 32 studies with 179,766 patients. A total of 31 studies containing 179,721 patients with localized and advanced prostate cancer were eligible for meta-analysis. In localized prostate cancer intraductal disease was associated with adverse outcomes including lower biochemical recurrence-free survival (pooled HR 2.09, 95% CI 1.75-2.50) and cancer specific survival (pooled HR 2.93, 95% CI 2.25-3.81). In advanced prostate cancer overall survival was lower in patients with vs without intraductal disease (pooled HR 1.75, 95% CI 1.43-2.14). Subgroup analysis by specimen type revealed that intraductal carcinoma of the prostate is a significant negative prognostic factor in both biopsies and prostatectomy specimens. Moreover, subgroup analyses based on the histopathological definitions of intraductal carcinoma of the prostate indicated that intraductal disease was significantly associated with lower biochemical recurrence-free, cancer specific and overall survival for almost all definitions. CONCLUSIONS: Intraductal disease is a histopathological feature of biologically and clinically aggressive prostate cancer. It confers worse oncologic outcomes in both localized and advanced prostate cancer, whether assessed in biopsy or prostatectomy specimen. The pathologist should assess for and report on the presence of intraductal disease in all prostate specimens. The urologist and radiation oncologist should consider this adverse feature in their clinical decision making.